Methods and apparatus for endovascularly replacing a patient's heart valve

Abstract

The present invention relates to an apparatus for replacing a native aortic valve, the apparatus includes an expandable anchor adapted to be endovascularly delivered and secured at a site within the native aortic valve. The expandable anchor has a delivery length in a delivery configuration substantially greater than a deployed length in a deployed configuration. The apparatus may also include and a replacement valve configured to be secured within the anchor.

Description

CROSS REFERENCE[0001]This application is a continuation-in-part application of U.S. Ser. No. 10 / 746,280, filed Dec. 23, 2003.BACKGROUND OF THE INVENTION[0002]Heart valve surgery is used to repair or replace diseased heart valves. Valve surgery is an open-heart procedure conducted under general anesthesia. An incision is made through the patient's sternum (sternotomy), and the patient's heart is stopped while blood flow is rerouted through a heart-lung bypass machine.[0003]Valve replacement may be indicated when there is a narrowing of the native heart valve, commonly referred to as stenosis, or when the native valve leaks or regurgitates. When replacing the valve, the native valve is excised and replaced with either a biologic or a mechanical valve. Mechanical valves require lifelong anticoagulant medication to prevent blood clot formation, and clicking of the valve often may be heard through the chest. Biologic tissue valves typically do not require such medication. Tissue valves m...

AI Technical Summary

Problems solved by technology

Valve replacement surgery is a highly invasive operation with significant concomitant risk.

Risks include bleeding, infection, stroke, heart attack, arrhythmia, renal failure, adverse reactions to the anesthesia medications, as well as sudden death.

Some self-expanding valve anchors have had very poor accuracy in deployment, however.

The stent often jumps to another position once released, making it impossible to know where the ends of the stent will be after release with respect to the native valve, the coronary ostia and the mitral valve.

Due to the jumping action of some self-expanding anchors, and because the replacement valve is often not fully functional before final deployment, visualization of valve function and position prior to final and irreversible deployment is often impossible with these systems.

Another drawback of prior art self-expanding replacement heart valve systems is their relative lack of radial strength.

Expandable stent designs suitable for endovascular delivery for other purposes may not have sufficient radial strength to serve as replacement heart valve anchors.

However when the stent has a valve fastened inside it, and that valve must reside within the heart, as is the case in aortic valve replacement, the anchoring of the stent to vessel walls takes significantly more radial force, especially during diastole.

Moreover, a self-expanding stent without sufficient radial force will end up dilating and contracting with each heartbeat, thereby distorting the valve, affecting its function and possibly causing it to migrate and dislodge completely.

Simply increasing strut thickness of the self-expanding stent is not a good solution as it increases profile and / or a risk of plastic deformation of the self-expanding stent.

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